allow(unsafe_op_in_unsafe_fn) on some functions

These need to get their safety story straight

std/src/sys/pal/windows/pipe.rs

@@ -1,4 +1,3 @@
-#![allow(unsafe_op_in_unsafe_fn)]
 use crate::os::windows::prelude::*;
 
 use crate::ffi::OsStr;
@@ -325,6 +324,7 @@ impl AnonPipe {
     /// [`ReadFileEx`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-readfileex
     /// [`WriteFileEx`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-writefileex
     /// [Asynchronous Procedure Call]: https://docs.microsoft.com/en-us/windows/win32/sync/asynchronous-procedure-calls
+    #[allow(unsafe_op_in_unsafe_fn)]
     unsafe fn alertable_io_internal(
         &self,
         io: AlertableIoFn,
@@ -561,12 +561,14 @@ impl<'a> Drop for AsyncPipe<'a> {
     }
 }
 
+#[allow(unsafe_op_in_unsafe_fn)]
 unsafe fn slice_to_end(v: &mut Vec<u8>) -> &mut [u8] {
     if v.capacity() == 0 {
         v.reserve(16);
     }
     if v.capacity() == v.len() {
         v.reserve(1);
     }
+    // FIXME: Isn't this just spare_capacity_mut but worse?
     slice::from_raw_parts_mut(v.as_mut_ptr().add(v.len()), v.capacity() - v.len())
 }

std/src/sys/pal/windows/thread.rs

@@ -1,4 +1,3 @@
-#![allow(unsafe_op_in_unsafe_fn)]
 use crate::ffi::CStr;
 use crate::io;
 use crate::num::NonZero;
@@ -23,6 +22,8 @@ pub struct Thread {
 
 impl Thread {
     // unsafe: see thread::Builder::spawn_unchecked for safety requirements
+    #[allow(unsafe_op_in_unsafe_fn)]
+    // FIXME: check the internal safety
     pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> {
         let p = Box::into_raw(Box::new(p));
 
@@ -70,7 +71,7 @@ impl Thread {
     ///
     /// `name` must end with a zero value
     pub unsafe fn set_name_wide(name: &[u16]) {
-        c::SetThreadDescription(c::GetCurrentThread(), name.as_ptr());
+        unsafe { c::SetThreadDescription(c::GetCurrentThread(), name.as_ptr()) };
     }
 
     pub fn join(self) {